1. Field of the Invention
The present invention relates to an expansion valve, and more particularly to a thermostatic expansion valve suitable for use in a refrigeration cycle.
2. Description of the Related Art
A refrigeration cycle in an automotive air conditioner generally includes a compressor for compressing a circulating refrigerant, a condenser for condensing the compressed refrigerant, an expansion valve for throttling and expanding the condensed liquid refrigerant and delivering the resulting spray of refrigerant, and an evaporator for cooling the air in a vehicle interior using evaporative latent heat of the refrigerant. The expansion valve is, for example, a thermostatic expansion valve that senses the temperature and the pressure of the refrigerant on the outlet side of the evaporator and adjusts the valve opening degree so that the refrigerant delivered from the evaporator has a predetermined degree of superheat, to control the flow rate of the refrigerant to be delivered to the evaporator.
Such an expansion valve has a body in which a first passage through which the refrigerant flowing from the condenser toward the evaporator passes and a second passage through which the refrigerant having returned from the evaporator passes are formed. The first passage includes a valve hole, and a valve element disposed facing the valve hole. The valve element moves toward and away from the valve hole to regulate the flow rate of the refrigerant flowing toward the evaporator. A power element that senses the temperature and the pressure of the refrigerant flowing through the second passage and operates in response to the sensed temperature and pressure is provided at one end of the body. The drive force of the power element is transmitted to the valve element via a shaft. The shaft extends through an insertion hole formed in a partition that separates the first passage from the second passage, and is supported slidably against the body. One end of the shaft is connected to the power element, and the other end thereof extends through the valve hole and is connected to the valve element (refer to Japanese Unexamined Patent Application Publication No. 2013-242129, for example).